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Modules

Observability

Observability

Two modules provide observability: failover-observable-scanner discovers @Failover methods at startup; failover-observable-micrometer adds Micrometer counters and a health indicator.

failover-observable-scanner

Walks the Spring ApplicationContext at startup, finds all @Failover-annotated methods, and registers them with the ObservablePublisher.

<dependency>
    <groupId>com.societegenerale.failover</groupId>
    <artifactId>failover-observable-scanner</artifactId>
    <version>3.0.0</version>
</dependency>

At startup, the scanner logs a summary:

INFO  FailoverScanner: Discovered 5 @Failover methods:
  - country-by-code    (domain=country, expiry=24h)
  - all-countries      (domain=country, expiry=24h)
  - product-by-id      (expiry=6h)
  - exchange-rates     (expiry=1h)
  - client-profile     (expiry=12h)

The scanner also warns when two @Failover annotations share a domain but have mismatched expiry configurations.

failover-observable-micrometer

Extends the scanner with Micrometer counters and a Spring Boot Actuator health indicator.

<dependency>
    <groupId>com.societegenerale.failover</groupId>
    <artifactId>failover-observable-micrometer</artifactId>
    <version>3.0.0</version>
</dependency>

Includes failover-observable-scanner transitively.

Micrometer Counter

Counter name: failover.store

Tag Values
name The @Failover(name=...) value
action store, recover, nonRecover, cleanByExpiry

Health Indicator

Registered at /actuator/health under the failover component:

{
  "failover": {
    "status": "UP",
    "details": {
      "enabled": "true",
      "type": "BASIC",
      "store.type": "JDBC",
      "store.jdbc.table-prefix": "MYAPP_",
      "scheduler.enabled": "true"
    }
  }
}

ObservablePublisher SPI

AdvancedFailoverHandler calls ObservablePublisher.publish(Metrics) after every store and recover event. Implement this interface to route metrics to any custom sink:

@Component
public class MyPublisher implements ObservablePublisher {
    @Override
    public void publish(Metrics metrics) {
        log.info("failover event: name={} action={} duration={}ns",
            metrics.getName(),
            metrics.get("action"),
            metrics.get("duration-ns"));
    }
}

Metrics.toMap() returns all key/value pairs collected during the operation.

Next Steps